In grocery stores, supermarkets, and butcher shops a paper pulp or polystyrene foam tray with a meat, cheese, or poultry product therein and overwrapped by a sheet of plastic film is a very familiar package. Often these packages are wrapped manually with the film folded or tucked under the bottom of the tray and the tray is then passed over a hot plate to seal it. In order to increase production and lower labor costs, automatic wrapping devices have been introduced. Typical of these is the apparatus described in U.S. Pat. No. 4,631,903 which issued on Dec. 30, 1986 to Yoshiyuki Takamura.
One of the drawbacks in both hand wrapping and in the prior automatic machinery processes is that the film is not folded smoothly under the bottom of the tray. When this occurs and there is a "bunching" of the film underneath the tray. Additional time must be taken to seal the thick bunch of film so that a package can be made that will maintain its integrity throughout the distribution cycle. In addition, such seals usually will not result in a leakproof package so that fluids from the meat or poultry product will leak through the seals thus presenting an unsightly package which will often be rejected by the shopper. Accordingly, it is one object of the present invention to provide a device and method for producing a smooth, leakproof seal on the underside of a tray.
In order to produce packages which secure the product within the package so that it will not unnecessarily move around and also to produce a neater and more attractive package, often a heat shrinkable film is used to overwrap a tray filled with a meat or poultry. Unless a secure seal is produced on the bottom side of a tray when the film is shrunk, the seal will pull apart. Accordingly, it is another object of the present invention to provide a secure seal on the underside of the tray that will withstand shrinking tension.
A further object of the invention is to provide a method and apparatus for packaging with a full range of tray sizes without having to adjust or change the folding arms.
Yet another object of the present invention is to provide packages with smoother seals on the bottom thereof for easier handling, stacking, and display.
Still another object of the present invention is to provide a package which requires a minimum amount of film.
These and other objects of the present invention will be readily appreciated by reference to the summary of the invention, drawings appended hereto, and the detailed description which follow.